another gourami? thats kinda pushing it isnt itI agree with saltynav. I would look to sell the plec (if you can back), maybe back to the shop where you got it? Then, bring up the shoal of Corydoras to about 5 or 6. Possibly look at getting another gourami or two and then pop back on!
There would still be room for some more but I would sort out the community you have first.